openlp 1.9.8 with mysql backend on MacOsX

I was trying to set mysql as a backend for songs on Openlp 1.9.8 on MacOS X Lion according to the instructions at wiki.openlp.org. I was trying to change the mac confituration file /Users/<user>/Library/Preferences/org.openlp.OpenLP.plist and put there values

but unfortunately it does not work. The local sqlite database is still beign loaded. Moreover I think that this part: "(Advanced) Using MySQL or PostgreSQL to store songs part for MacOsX" of wiki is wrong, because org.openlp.OpenLP.plist is a xml file which cannot contain values in the form:

My question is, if it is possible to use MySql backend for Mac version of OpenLP as well or that is just for linux and windows version (which I succesfully tested with mysql). If yes, what is the correct configuration settings for Mac? Which configuration file needs to be changed?